Process of cracking petroleum hydrocarbons



C. R. DOWNS April 9,1929. I

. PROCESS OF CRACKING PETROLEUM HYDROCARBONS Filed Dec. 1, 1925 Magiflbyw-z/ wf 731. M 4 A fl'orhey Patented Apr. 9, 1929.

-UNITED STATES PATENT OFF-ICE.

"CHARLES RAYMOND DOWNS, OF NEW HAVEN; CONNECTICUT, ASSIGNOR TO WEISS ANDDOE/NS, ING, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROCESS OF GRACKING PETROLEUM HYDROCARBONS A lication. filed December 1,1925. Serial No. 72,422.

In a copending application, Serial No.

- 692,223, filed February 12, 1924, I have dis closed the use of boilingsulphur as-a method of heating bituminous materials such as tarsor'petroleums or their distillates in such a way that distillation willtake place with the least amount of superheating and cracking. Thisprocess was based on the fact that the use ofa boiling liquid as aheating means, especially where the heat transfer takes place throughthe medium of condensation of the vapors of the boiling liquid, gives ahigh rate of heat input without a large temperature differential.

In the petroleum industry much use is made of the type of distillation,destructive in character, which is known as cracking. This involves thesubjection of selected frac tions'of the oil to such temperatures aswill decompose tliem into lighter hydrocarbons, preferably of thegasoline type. In these processes the control of the temperature of theoil beingcracked is important as it must be high enough to enabledecomposition to take place but not so high as to cause furtherdecomposition into. excessive amounts of permanent gases, aromatichydrocarbons, tar, etc.

i The invention herein described comprises the extension of theprinciple described in Serial No. 692,223 to cover the use of boilingsulphur as a means of heating in processes designed for the crackingdistillation of petroleum products. many various types and I do notconfine myself to the application of the boiling sulphur-heating meansto any one type. Those processes in commercial use to-day operate mostefliciently over a range of temperature from 750 F. to 950 F., orthereabouts, the optimum temperature for any specific case varying. withthe particular oil fraction be-'- ing treated, the nature of thecrudepetro leum from which it was obtained, thepres-u sure under which theon, etc; V

Over this range of temperature, sulphur -with a boiling point at sealever of 832 F.

can be made to maintain a constant and unioperation is carried formtemperature by regulation ofthe pressure on the sulphur system, beingvaried above, {at or below atmospheric pressure, according to theparticular temperature desired. Ingene'ral, the use of absolutepressures between 9 lbs. and 50 lbs. per sq. in.

These are of gives a suflicient range for practical operation. .The useof the latent heat of condensation of sulphur vapor as a heat'supplyrenders it possible t'o obta'in high rates of heat flow without hightemperature differ- .entials, thereby enabling the cracking temperatureto be maintained at. the optimum, point desired, without thepossibilityof excessive temperatures and further decomposition into undesirableproducts.

In order to describe the invention I give the following exampleaccompanied by the drawing which is diagrammatic only. The example isfor illustrative purposes only and I do not intend to limit myselfthereby.

Numeral 1 represents a sulphur boiler. The boiler is set in a furnace 2with firebox 3" and exit 4 to a stack (not shown) to al low the escapeof the combustion products. The boiler connects by a pipe 5 to a jacket6 containing the oil heatingelement 7 which may, for exa u'lple, be apipe coil. The jacket 7 connects by a pipe 8 to a pressure regulatingtank 9 with gauge l0 and pipe 11 for the introduction of an inert gasfrom a .pump or other pressure source;

In operation, the oil to be cracked enters in the" direction of thearrow at 12 and if desired may pass througha preheating coil 13 set inthe cooler portion pf the furnace2, or be preheated in any otherconvenient way.

It thenpasses to the coil 7 in the sulphur 1 heating jacket 6 and exitsinthe direction of the arrow at 14 dischargingto condensers,

reaction chambers pressure reducing valves, vapor boxes, bubble towers,or whatever dewoe is used 1n the part cular cracking system to whichthis heating means is applied.

Sulphur is boiled in "the boiler 1, the vapors pass ng by the pipe 5 tothe jacket 6 where by condensing they give u'p their heat to the oilpassing through the 001i 7 The conclensed sulphur returns through thepipe 5 to the boiler 1. n By maintaining a suitable inert gas pressureon'the tank 9, the boiling point of the sulphur may be fixed at apredetermined point, above which the oil in the pipe 7 cannot be heated.'The tank 9 1s not essential to the invention as the jacket 6 may carrya pressure gauge and inert gas from a pressure source applied directlytothe jacketj In this process the vapors of the sulphur do not comeintodirect contact with the oil to be heated but are separated from it bymetal or other malace.

- heating of the oil ma be in containers other than coil-shaped an ingeneral, Ido not intend to limit myself in any way by the specificdetails of the construction shown. It is my intention to cover broadlythe use of boiling sulphur-tor condensing sulphur vapor as a means ofheating oils of any kind, but more especially petroleum oils to a termperature suitable for cracking the oil. The oil cracking itself maybecarried on at,

above or below atmospheric pressure, de-

pending on the particular cracking system 'to which my method of heatingis ap lied.

Having described my invention, I c aim: 1. In cracking petroleumproducts, the

step which comprises heating them by means f of the vaporsof boiling suThe boiler used may 'be of any type, the

temperature of the said sulphur vapors by the pressure applied thereto.

2 In cracking petroleum roducts, the step which comprises heatin t cm bymeans of the vapors of boiling suIphur' out of direct contact therewithbut in heat transferring relation thereto-and regulating the tem Yperature of the said sulphur vapors by the pressure applied thereto bymeans of a' neutral fixed gas.

3. In cracking petroleum ring relation thereto and regulating thetemperature of the said sulphur vapors by the pressure applied theretoby means of a neutral fixed gas at greater than atmospheric press e.

rect contact-therewith but in heat transfersignature.

ring relation thereto and regulating the CHARLES Ramona DOWNS.

roducts, the step which comprises heatin t em by means phur out of di;In testimony whereof, I hereby aflix my I

